Purpose Three-dimensional (3D) printing provides more possibilities for composite manufacturing. Composites can no longer just be layered or disorderly mixed as before. This paper aims to introduce a new algorithm for dual-material 3D printing design. Design/methodology/approach A novel topology design method: solid isotropic material with penalization (SIMP) for hybrid lattice structure is introduced in this paper. This algorithm extends the traditional SIMP topology optimization, transforming the original 0–1 optimization into A–B optimization. It can be used to optimize the spatial distribution of bi-material composite structures. Findings A novel hybrid structure with high damping and strength efficiency is studied as an example in this work. By using the topology method, a hybrid Kagome structure is designed. The 3D Kagome truss with face sheet was manufactured by selective laser melting technology, and the thermosetting polyurethane was chosen as filling material. The introduced SIMP method for hybrid lattice structures can be considered an effective way to improve lattice structures’ stiffness and vibration characteristics. Originality/value The fabricated hybrid lattice has good stiffness and damping characteristics and can be applied to aerospace components.

As a representative fluid-transporting system, fluid-conveying pipes play an essential role in many fields. For a fluid-conveying pipe system in operation, fluid pulsation in pipes contains much information about fluid flow parameters (flow velocity, fluid pressure, etc.). Therefore, the measurement of fluid pulsation is important for understanding the internal fluid flow. To use polyvinylidene fluoride (PVDF) piezoelectric film sensors to indirectly measure the pressure fluctuation of the internal fluid, we simulated a fluid-conveying pipe with PVDF piezoelectric film sensors attached to the outer pipe wall. The simulation results showed that the variation of voltage signal of PVDF, circumferential stress and strain of the pipe wall, and the pressure fluctuation of internal fluid were highly positively correlated, which proved that the PVDF piezoelectric film sensor can be applied to indirectly measure the pressure fluctuation of internal fluid. We also studied the influences of flow velocity pulsation and mechanical vibration caused by the pipeline pump during operation. It is found that the flow velocity pulsation had little influence on the measurements of the variation of circumferential stress and strain of the pipe wall and the internal fluid pressure fluctuation. When both ends of the pipe were fixed by hoops, mechanical vibration had little influence on the measurement of the variation of circumferential stress and strain of the pipe wall as well as the fluid pressure fluctuation. Finally, simulation results were verified by experiments.

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